Sort of in the same vein as Bi directional Socket question:

I can't get a pair of processes to communicate by socket, under Win98 with ActiveState perl 5.6.1.

I've read the Perl Cookbook ch. 17 advice, and also the relevant sections of Mastering perl/Tk (since that's what I'm trying to do, move some heavy lifting to a separate process so as not to slow down GUI response). What I'm doing, I think, is right in line with their recommendations. I've tried various permutations of parameters, with no success.

Code is below. When I run it, I get the following messages: 

child started IO::Socket::INET=GLOB(0x204aeb8)
child read failed: Invalid argument at E:\Perls\sock_hop.pl line 63.
parent started IO::Socket::INET=GLOB(0x176541c)
parent sending
parent sending
parent sending
parent write failed: Invalid argument

[download]

... of which the failed read in the child seems to be the smoking gun. "Invalid argument" presumably refers to the file handle -- but what's its problem?

If anyone here can take a minute to look at the attached code snippet, I'd be grateful.

--Dinosaur 

use strict;
use warnings;

use IO::Socket;

sub process;
sub parent;
sub child;

use vars qw[$PARENT $CHILD];

process;
exit;

sub process {

   $PARENT = IO::Socket::INET->new(
                 Type => SOCK_STREAM,
                 Proto => 'tcp',
                 LocalHost => 'localhost',
                 LocalPort => 9969,
                 Listen => 5,
                 );
   die "parent socket failed: $!\n" unless defined $PARENT;
    
   $CHILD = IO::Socket::INET->new(
                 Type => SOCK_STREAM,
                 Proto => 'tcp',
                 PeerAddr => 'localhost',
                 PeerPort => 9969,
                 );
   die "child socket failed: $!\n" unless defined $CHILD;
    
   if (my $pid = fork()) {
      close $PARENT;
      parent;
   } else {
      die "fork failed: $!\n" unless defined $pid;
      close $CHILD;
      child;
   }

}

sub parent {

   print STDERR "parent started $CHILD\n";

   while (1) {
      print STDERR "parent sending\n";
      print $CHILD "Hello from parent\n" or die "parent write failed: 
+$!\n";
      sleep 2;
   }
    
}

sub child {

   print STDERR "child started $PARENT\n";

   while (1) {
      my $line = readline ($PARENT);
      die "child read failed: $!" unless defined $line;
      print STDERR $line;
   }

}

[download]

In reply to Win98 socket woes by Dinosaur

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.